ROSEMOUNT 644 TEMPERATURE TRANSMITTER ASSEMBLY PRE OWNED/ NORMAL WEAR/ UNTESTED/ WE WERE TOLD THIS WAS PULLED FROM WORKING ENVIRONMENT BUT CANNOT TEST ANY FURTHER SO WE ARE SELLING AS IS Rosemount 644 is a versatile, smart temperature transmitter available in head?mount and field/rail?mount versions with HART, FOUNDATION Fieldbus, or PROFIBUS communication. Key features and I/O 2?wire device, outputs either 4?20 mA with HART or fully digital FOUNDATION Fieldbus / PROFIBUS PA depending on model option. Accepts universal inputs: RTD (e.g., Pt100), thermocouple, mV, or ohms; single or dual sensor capability (dual for HART models) with features like Hot Backup and sensor drift alerts. Typical reference accuracy is about 0.10 C for supported RTDs when properly configured and matched. Power, environment, and isolation External DC supply required; HART / 4?20 mA versions operate roughly from 12 to 42.4 V DC at the transmitter terminals (exact usable range depends on loop load). Input/output isolation tested to around 500?620 V AC rms (?700 V DC), enhancing reliability in noisy environments and meeting NAMUR NE 21 EMC recommendations. Ambient operating range commonly ?40 to 185 F (?40 to 85 C), depending on version and presence of LCD/display. Mounting and options Available as DIN A head?mount or compact rail/field?mount with various enclosure options and optional integral LCD display or Local Operator Interface (LOI) for in?field configuration. Certified for use in hazardous locations with appropriate approvals (ATEX, CSA, etc.), with specific temperature codes depending on power and ambient conditions. SHELF: 83 SA